Dyeing of organic derivatives of cellulose



Patented 5, 1937 UNITED STATS PATENT OFFICE DYEING or ononmo DERIVATIVES or cELrULosn tion of Delaware No Drawing. Application September 21', 1933, Serial 'No. 690,421. In Great Britain Qctober 6 Claims.

This invention relates to the manufacture of new azo dyestuffs and to the colouration therewith of textile and other materials, and in particular materials consisting-0f or containing cellulose acetate or other cellulose esters or ethers.

We have found that valuable new dyestuffs may .be obtained by coupling diazo compounds obtainable by diazotizing 4-amino-3-nitro-benzenes substituted in the 1-position by alkyl, alkyloxy or other etherified hydroxyl group, halogen, or other substituent, with B-amino-l-alkylor l-alkyloxy-benzenes which couple in the para-position to the amino group, for example meta-toluidine. Especially valuable dyestuffs may be obtained with the aid, as coupling components, of mono-amino-1:4dialkyl-, dialkyloxy-, or alkylualkyloxy-benzenes, for .instance para-xylidine. A particularly valuable dyestuff may be obtained by coupling diazotized 4-amino-3-nitro-1-methylbenzene with the aforesaid para-xylidine. By means of these dyestuffs valuable yellow to orange shades may be obtained upon cellulose ester or ether materials, which shades are characterized.

by excellent fastness properties and are readily dischargeable, for instance by means of reducing discharging agents.

In accordance with the present invention, therefore, new dyestufis are produced by coupling diazo compounds obtainable by diazotizing l-amino-3-nitro-benzenes substituted in the l-position by alkyl, alkyloxy or other etherified hydroxyl group, halogen, or other substituent, with B-amino-l-alkylor l-alkyloxy-benzenes capable of coupling in the para-position to the amino group. As examples of suitable diazo components, mention may be made, in addition to the aforesaid 4-amino-3-nitro-toluene, of 4-amino-3-nitro-l-methoxy or l-ethoxy-benzene and. 4-amino-3-nitro 1 chlorbenzene. Suitable coupling components are meta-toluidine and the monoamino-l :4-dialkyl-, dialkyloxyor alkyl-alkyloxybenzenes for example para-xylidine, para-cresidine and amino-hydroquinone-dimethyl-ether, or N-alkyl derivatives thereof e. g. dimethyl-mtoluidine.

'As previously mentioned, a particularly valuable dyestuff may be obtained by coupling diazotized 4-amino-3-nitro-toluene with para-xylidine.

This dyestuff dyes cellulose esters or ethers in orange shades which are readily dischargeable by means of reducing discharging agents, for example stannous chloride discharges or zinc formaldehyde sulphoxylate discharges. The dyestuif has, moreover, an excellent affinity for cellulose esters andethe'rs and exhibits very good levelling properties. Further, the dyeings obtainable with the aid of this dyestuff on cellulose acetate are substantially non-phototropic, whereas, as is wellknown, a large number of otherwise satisfactory yellow to orange dyeings on cellulose esters and ethers exhibit this defect to a high degree and are therefore commercially useless.

A particularly valuable application of this and other colouring matters of the present invention is forthe production in conjunction with navy blue dyestufis, of dischargeable black shades on cellulose esters or ethers, for example by first dyeing the materials in navy blue shades and thereafter topping the resulting dyeings with the yellow or orange dyestuffs or mixtures containing them. Valuable dischargeable black shades may for instance be produced .on cellulose acetate by dyeing first with para-amino-benzene-azo-dimethyl-aniline, diazotizing and developing with p-oxy-naphthoic acid to a navy blue shade, and thereafter topping with the orange dyestufi from 3-nitro-4-amino-toluene and para-xylidine.

The new colouring matters, as indicated above, are of especial value for the colouration of cellulose acetate and other cellulose ester or ether materials. As examples of such other esters and ethers reference may be made to cellulose formate, propionate or butyrate or the products obtainable by esterifying cellulose while retainingits fibrous form, or the ethyl, benzyl or other ethers of cellulose. They may also be applied to mixed materials comprising one or more of the aforesaid cellulose esters or ethers in admixture with other textile fibres, for example wool, silk or other animal fibres, or cotton, regenerated cellulose or other cellulosic materials. Such other fibers may be coloured by the same dyestuffs as the cellulose esters or ethers when they possess the requisite affinity, or they may be coloured either in the same or different shades by means of other dyestuffs, either before, after or simultaneously with the colouration of the cellulose esters or ethers.

Colouration with the new colouring matters is preferably effected with the dyestuffs in substance, for which process of application the dyestuffs are eminently suited owing to their good affinity. If desired, however, they may be formed on the material, for example by applying the diazo component and thereafter diazotizing and developing with the coupling component.

The colouring matters are conveniently applied to the materials in the form of aqueous suspensions or dispersions, though if desired they may be applied from solutions in organic or other solvents.

, colloids and/or liquids, e. g., water.

The new dyestufis may be obtained in dispersed form in any desired manner, for example by grinding, e. g., in colloid mills, by dissolving in a solvent and mixing with water containing or not containing protective colloids and/or dispersators, or by treatment with dispersing agents, whether alone or in the presence of protective Another method which may be employed is to efiect the coupling in the presence of protective colloids with or without dispersing agents. Any desired dispersators may be employed, for example any of those mentioned in prior U. S. Patents Nos. 1,618,413, 1,618,414, 1,694,413, 1,690,481, 1,803,008, ,840,572, and 1,716,721, and U. S. applications S. Nos. 390,423, filed 4th September, 1929, and 390,424, filed 4th September, 1929.-

The dispersion may be effected in the dyebath itself. Conveniently, however, the dyestufis are first brought into the form of more or less concentrated preparations, whether liquid or solid or semi-solid, adapted to yield by addition of water with or without further dispersation and/ or protective colloids, aqueous suspensions or colloidal solutions which may be directly employed for the colouration of cellulose acetate or other organic substitution derivatives of cellulose. These preparations are included within the scope of the invention.

If desired the physical properties of the dyestuffs of the present invention may be improved in the manner described in U. S. applications S.

, Nos. 660,856, filed 15th March, 1933, and 679,312,

The invention is illustrated but not limited by the following examples:

' Example I 550 grams of 3-nitro-4-amino-toluene and 255 grams of sodium nitrite are made into a thin paste with hot water. The cooled paste is then slowly run into 1100 cos. of hydrochloric acid 32 Tw. in 12 litres of cold water (10-15" C.). After stirring for 1-2 hours, the solution is run slowly into 437 grams of para-xylidine dissolved in 40 litres of water containing 450 ccs. of hydrochloric acid at 32 Tw. Stirring is continued for a time and then mineral acidity is neutralized by addition of sodium acetate solution and the dyestufi filtered off. It dyes cellulose acetate from an aqueous dispersion in orange shades readily dischargeable with zinc formaldehyde sulphoxylate.

Example II naphthoic acid. The material which is dyed in navy blue is then topped in a neutral or preferably slightly acidic bath with 0.1 to 0.15% on the weight of the goods of 2-nitro-4-methyl-benzene-azo-para-xylidine according to the shade of black desired. The fabric is then printed with a discharge paste having the following composition:

Parts Decrolin sol. conc 25 Diethylene glycol 10 Ethyl lactate 10 Gum arabic and water 55 and dried, aged for 5 minutes in a Mather & Platt ager, and washed off thoroughly and again dried when a white pattern is obtained on ablack ground.

Emample III 500 grams of a 10% aqueous paste of 2-nitro- 4-methoxy-benzene-azo-meta-toluidine are heated with 250 grams of Turkey red oil until a uniform dispersion is obtained. The dispersion is then diluted on boiling with 2.5 grams per litre soap. solution and the whole strained through muslin into 300 litres of a 0.5 gram per litre soap bath. A cellulose acetate woven fabric is entered into thisdyebath and the temperature raised to C., and maintained thereat ,until the requisite shade is obtained. The fabric is then rinsed and dried, a golden yellow shade being obtained. On printing locally with the discharge paste described in Example II a white discharge is obtained on a golden yellow ground.

What we claim and desire to secure by Letters Patent is: v

1. Process for the production of dischargeable blacks on textile materials of an organic derivative of cellulose, which comprises coloring the materials in a navy blue shade with a dischargeable dyestufi, and topping the materials with an orange or yellow dyestufi obtainable by coupling with a compound selected from the group consisting of B-amino-l-alkyl, and 3-amino-1-alky1- oxy compounds of th benzene series, a diazo compound obtainable by diazotizing a compound of the formula where X is alkyl, alkyloxy or halogen and the remaining positions of the benzene ring are occupied NH X where X is alkyl, alkyloxy or halogen and the remaining positions of the benzene ring are occupied by hydrogen. i

3. Process for the production of dischargeable blacks on cellulose acetate textile materials, which comprises coloring the materials in a navy blue shade with a dischargeable dyestufl, and topping the materials with a dyestufl' obtainable by couplingwith para-xylidine a diazo compound obtainable by diazotizing methyl-benzene. L V 4. Textile materials of an organic derivative 4-ainino-3nitro-fi- -of cellulose colored in a dischargeable black shade with a dischargeable navy blue dyestufl topped with an orange or yellow dyestufi obtainable by coupling with a' compound selected from the group consisting of 3-amino-1-alkyl, and 3-amino-1- alkyloxy compounds of the benzene series, a diazo compound obtainable by diazotizlng a compoundof the formula NH x where X is alkyl, alkyloxy or halogen and the remaining positions of the benzene ring are oc- 'cupled by hydrogen.

5. Textile materials of cellulose acetate colored in a dischargeable black shade with a dischargeahle navy blue dyestuii topped with an orange or yellow dyestufl obtainable by coupling with a compound selected from the group consisting of 3-amino-1-alkyl, and 3'-amino-'1-alky1oxy compounds of the benzene series a diazo' compound obtainable by diazotizing a compound of the formula i NO:

where X is allgvl, alkyloxy or halogen and the remaining positions of the benzene ring are occupied vby hydrogen.

6. Textile materials of cellulose'acetate colored 

